As the development of the computer industry and the tendency towards diversification of the electronic apparatus, the integration of the electronic elements on printed circuit board is increased, and the insulation and heat-dissipation issues of the electronic elements become more and more important. Particularly, the power transistor, which is commonly used in many control equipments, measuring devices, electric appliances and peripheral apparatuses, generates higher heat since it functions for signal processing and power driving and usually deals with high power signal, and thus, the insulation and heat-dissipation problems thereof need to be solved.
In general, a power transistor is fastened on a heat sink to enhance the heat-dissipating effect thereof. Please refer to FIG. 1, which is an exploded view showing a conventional power transistor fastened on a heat sink. As shown in FIG. 1, a power transistor 12 is fastened on a heat sink 14 by a screw 11. In order to improve the insulating and heat-dissipating effect, an insulating piece 13 is disposed between the power transistor 12 and the heat sink 14, and the insulating piece 13 is coated with heat-dissipating paste on both sides. Due to the insulating piece 13 is usually made by a thin and plastic slice and the heat sink 14 is made by a conductive metal, the screw 11 may pierce or destroy the edge of the through hole 131 of the insulating piece 13 when the screw 11 is inserting through the through hole 131 of the insulating piece 13. Moreover, an ill-designed insulating piece 13 cannot provide enough insulating distance and further leads to electric arcs, sparks or smog resulted from a short circuit taken place between the power transistor 12 and the heat sink 14 when the power transistor 12 is operated under high voltage. However, as the operation power of the power transistor 12 is raised, the problem mentioned above will more seriously and indirectly affect the stability of the product assembly.
Therefore, it is needed to develop an assembly structure of an electronic element and a heat sink to solve the aforesaid problems and provide a more effective insulating and fastening apparatus to enhance the insulating and heat-dissipating effect.